Parse 'fortnight' as a duration of two weeks

plugins/dates/src/api/parse/one/01-tokenize/01-shift.js

@@ -18,6 +18,11 @@ const aliases = {
   weekend: 'week', //for now...
 }
 
+// units made of other units
+const multiples = {
+  fortnight: [2, 'week'],
+}
+
 // half of a unit, in smaller whole units
 const halfUnits = {
   year: [6, 'month'],
@@ -53,9 +58,14 @@ const parseShift = function (doc) {
 
   // '5 weeks'
   shift.match('#Cardinal #Duration').forEach((ts) => {
-    const num = ts.match('#Cardinal').numbers().get()[0]
+    let num = ts.match('#Cardinal').numbers().get()[0]
     if (num && typeof num === 'number') {
-      const unit = parseUnit(ts)
+      let unit = parseUnit(ts)
+      // '1 fortnight' is 2 weeks
+      if (Object.hasOwn(multiples, unit)) {
+        num *= multiples[unit][0]
+        unit = multiples[unit][1]
+      }
       if (knownUnits[unit] === true) {
         result[unit] = isNegative ? num * -1 : num
       }

plugins/dates/tests/to-iso.test.js

@@ -156,6 +156,8 @@ test('date-parse :', function (t) {
     ['in 1 year', '2020-02-02T00:00:00.000Z'],
     ['3 days ago', '2019-01-30T00:00:00.000Z'],
     ['2 weeks ago', '2019-01-19T00:00:00.000Z'],
+    ['in a fortnight', '2019-02-16T00:00:00.000Z'],
+    ['1 fortnight ago', '2019-01-19T00:00:00.000Z'],
     ['1 month ago', '2019-01-02T00:00:00.000Z'],
     ['1 year ago', '2018-02-02T00:00:00.000Z'],
     ['at 4pm', '2019-02-02T16:00:00.000Z'],